Re: IML: rheostat on the dashboard dimmer wheel for my 68

[Christopher H <imperial67@xxxxxxxxxxxxx>]

Title: Re: IML: rheostat on the dashboard dimmer wheel for my 68

Tom,

Please do an archive search on the club website about this topic, as it’s been covered at length and should provide the help you need.

Quick answer, however, is that the thumbwheel is like two switches in one. To control the panel lights, a striker rod passes over a resistor block, decreasing the resistance in the circuit to make the dash lights brighter. When it gets all the way to the far side of the block (when you feel the slight detent), it then connects to a terminal that completes the circuit for the room lamps.

It’s like a basketball player running up the court and finally scoring. Your basketball player’s shoes or the court must be really dirty that 100 layups didn’t bring back the dash lights. The striker rod might not be contacting the resistor for some reason, so it’s time to (a.) check the archives and (b.) take the instrument panel out so you can get to the back of the panel rheostat and take a look.

While you’re there, you can change out all the little bulbs in the back of the cluster in case all of them are blown, but a more accessible one to check (I think the ’68 still has this; the ’67 does) is in the driver’s door armrest, illuminating the window switches. Or turn on the radio and the parking lights. I’m pretty sure the radio light should dim with the rest of the panel, so if it’s out too, you’ve pretty much eliminated every lamp on that circuit and odds are good the rheostat is the culprit.

I am assuming you checked/changed the fuse for the instrument lamps, by the way! It’s in the fuse block, the first one on the end (labeled INSTR LPS).

Let us know how it works out!

Chris in LA
67 Crown
78 NYB Salon


On 11/8/06 4:27 AM, Crestonave@xxxxxxx at Crestonave@xxxxxxx wrote:

> In a message dated 11/8/2006 3:17:17 A.M. Eastern Standard Time, mailing-list-owner@xxxxxxxxxxxxxxxx writes:
> > The rheostat  is defective, or just dirty/corroded from disuse.  
> MIchael and all:
>  
> I've already moved the thumbwheel through it's travel several hundred times at least. Still no dash lights. What I don't understand is that it will activate the rear courtesy lights but not the dashboard lights. Does this fact still indicate that the problem is in the thumbwheel? As to disassembling and cleaning, what's the best process for cleaning? Very light sanding? Chemical? 
>  
> Thanks!
>  
> Tom 
> 68 crown convert
> 60 nyer coupe